In Search of a Sensible Sound Transit Expansion Plan


Seattle Subway has proposed an alternative to Sound Transit 3 (ST3) called “STcomplete” that would double the project timeline from 15 to 30 years and allow Sound Transit to “complete” the network, rather than going back to the voters to approve further funds after first $15 billion is spent.

STcomplete would allow Sound Transit to offer benefits to the whole electorate, Seattle Subway argues. By contrast, $15 billion planned for ST3 is not enough to build rail near every major constituency voting on the measure. And since Sound Transit Board of Directors seems to be prioritizing very expensive rail to West Seattle, Seattle’s portion may not stretch very far at all.

Seattle Subway latest map shows rail from Tacoma to Everett and as far east as Issaquah. (Seattle Subway)
Seattle Subway latest map shows rail from Tacoma to Everett and as far east as Issaquah. (Seattle Subway)

Seattle Subway plans to exploit the fact that Olympia hasn’t set a sunset clause on Sound Transit’s taxing ability. They could raise a billion dollars a year indefinitely. Sound Transit would be within its legal parameters to put a 30-year, $30 billion proposal on the ballot with a wider selection of improvements to entice voters. Per year, the funding commitment doesn’t go up. It’s just a longer commitment.

The possibility of funding an extensive network in one fell swoop is tantalizing. The risk of Seattle Subway’s approach is that it could give fiscal conservatives and anti-transit folks enough ammunition to shoot down the ballot measure, sending us back to square one.

Meanwhile, Seattle Transit Blog has presented what they call a “peanut butter plan” using bus rapid transit (BRT) to stretch higher quality service to West Seattle and points south, and still allow enough money for the for the Ballard to UW rail line sometimes called the “Ballard Spur”. It’s a refreshing approach, but would BRT be enough to seriously improve the transit experience in outer Seattle and get people to vote for ST3?

Red lines denote BRT, the thick blue line represents the WSTT, a second downtown transit tunnel to relieve pressure on the current one and speed up service. (Frank Chiachiere/Seattle Transit Blog)
Red lines denote BRT, the thick blue line represents the WSTT, a second downtown transit tunnel to relieve pressure on the current one and speed up service. (Frank Chiachiere/Seattle Transit Blog)

Both plans address the troubling direction Sound Transit seems to pushing ST3 in Seattle. The West Seattle to Ballard light rail line is expected to cost upwards of $7 billion, exhausting the entirety of Seattle’s subarea funds. The Ballard Spur subway can connect Ballard to Downtown via Link at almost the same travel time as the more expensive Interbay route, and it would pick up Upper Fremont and Wallingford along the way. Interbay, on the other hand, is lightly populated and not much of a destination.

Sound Transit estimated the Ballard Spur subway (the A3 option) would cost between $1.4 billion and $1.9 billion. However, their initial study included only one station between Ballard and the University District, a glaring oversight. Seattle Subway issued a A4 plan that rectified that, including stations for West Ballard, East Ballard, Upper Fremont, Wallingford, and the University District. The two additional stations would bump up the cost, but $2 billion is a fair ballpark estimate and would still be a bargain considering how substantially the subway would improve on the tortuously slow Route 44 bus, and provide a 20-minute ride to from Ballard to Westlake Station crushing the times of the RapidRide D Line (about 30 minutes on a good day, but often much longer).

The Ballard Spur alignment. (Seattle Subway)
The Ballard Spur alignment. (Seattle Subway)

Meanwhile, tunneling directly from Ballard to Downtown via Interbay causes costs to balloon above $3 billion, according to Sound Transit’s study. Plus, I imagine engineering a tunnel underneath Salmon Bay could be challenging and lead to cost overruns. If we don’t build a Ship Canal tunnel, we’re stuck with reliability issues since a bridge has to go up or swivel to allow ship traffic to pass. And a lift bridge or a swivel bridge ain’t cheap either. The Interbay alignment would be faster to Downtown, but would not address the issue of slow east-west movements. I’m not saying never build the Interbay route — which not only could be faster for Ballardites, but also connect Lower Queen Anne and Belltown along the way — I just think the Ballard Spur is a higher priority.


This is where STcomplete pulls away from ST3. Conceivably, STcomplete could allow us to build both the Ballard Spur and the Ballard to West Seattle line in time. The sting of whichever route they choose to build first will be lessened by knowing another option will be on the way eventually. There is some argument about whether light rail is even the right solution for West Seattle, but at least if we are going to make the huge investment to built a questionable light rail line, it won’t be one of the only things Seattle proper gets out of the next ST package.

So push the Sound Transit Board of Directors to put STcomplete on the ballot November 2016, or at least to prioritize the right projects in ST3. Below is how I would prioritize for Seattle. Granted, Sound Transit might need to be dragged kicking and screaming into boring a urban subway like the Metro 8 (replacing the Route 8 bus). Still, we are allowed to dream.

  1. Ballard Spur subway –  $2 billion – 4 miles
  2. Metro 8 Subway phase one – $3 billion – 4 miles
  3. Metro 8 Subway phase two – $2 billion – 3 miles
  4. Full BRT improvements for West Seattle – S1 billion – 8 miles
  5. Downtown to Ballard subway – $2.5 billion – 3.5 miles (sharing tunnel with part of Metro 8)
  6. Ballard to Crown Hill to Northgate – $2 billion – 4.5 miles
  7. Northgate to Lake City – $1 billion – 2 miles

I’m totally spitballing with the budgets. Inflation alone could drive the project costs way up over a hypothetical STcomplete’s 30 year life span.

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Doug Trumm is The Urbanist's Executive Director. An Urbanist writer since 2015, he dreams of pedestrianizing streets, blanketing the city in bus lanes, and unleashing a mass timber building spree to end the affordable housing shortage and avert our coming climate catastrophe. He graduated from the Evans School of Public Policy and Governance at the University of Washington. He lives in East Fremont and loves to explore the city on his bike.

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frank discussion

I agree, Ballard to UW should be a part of ST-3. With Ballard as a growing residential and commercial area, going to/from Ballard to/from points north (yes, Ballardites work in Everett and people in Shoreline work in Ballard, and neither wants to go via downtown!) and not just downtown would be optimized by this decades-overdue solution. My second choice would be a West Seattle solution (downtown, e.g. the Stadium station) to West Seattle. I’d leave the “where” in West Seattle to those who live/work there.

For the north sub-area, I’d go direct (I-5) to Everett: 44% lower operating and maintenance costs, $2 billion less in capital costs, and about the same estimate for ridership, which is the softest of the estimated numbers. There’s no compelling reason to divert trains to Paine Field when BRT is slated to go there from the southeast, same routing from I-5, and where present demand for transit has been light, which is why cuts made back in 2003 and 2010 have not been restored. The dollar savings could finish the Ash Way direct access ramp and improve the 128th interchange.

For the east sub-area, I’d reluctantly choose BRT on I-405 as the top priority, though I think the board missed the boat by not pushing for light rail for particularly the highly-congested South Bellevue to Renton segment, ideally all of the way to the Tukwila International Station. For the south sub-area, I’d advise as far south as can be afforded, at least to the Tacoma Mall, via light rail.

Jason Siperly

Sorry, but if West Seattle is not included in light rail expansion, we will vote this down. A fifth of this city’s population resides in West Seattle and I know people over here are hopping mad with all the development over here without any transit upgrades. Furthermore, rightly or wrongly, the people over here have felt for a long time like we get shafted by the city when it comes to infrastructure. And the obvious disdain that you use when talking about light rail to West Seattle is playing right into this sentiment.

Jason Siperly

I absolutely support ST complete! In fact, because of the urban/suburban political divide in the region, I suspect Complete is the only way this will ever get done. But I also think that pitting urban neighborhoods against each other for rail service is going to play right into the no voters hands. And more than anything would be what ultimately kills it. My only real gripe is that this should have been done 30 years ago.

Ryan Countryman

Great ideas on rail! The Ballard spur makes especially good sense given the way that area is building up. Cars and busses lose their appeal when the existing roads are gridlocked. Give people options like rail on a separate network and they will ride it.

While I get that Seattle Subways’ emphasis is on Seattle proper, I think a truly complete system would include more for the suburbs too. People commute from places such as Marysville and Arlington into Seattle. It would make sense to add these cities to the taxing district for Sound Transit so that northern rail can be extended faster, thereby more quickly reducing the number of cars heading into Seattle. Similarly, the line going to Downtown Renton should extend north to Bellevue in order to give a direct connection between Bellevue and SeaTac. This would also help relieve road and rail chokepoints in Seattle. If only money were not an issue…